UN/NA Number Reference
DOT Class 2.3 Toxic Gas placard

UN 1026: Cyanogen

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1026 is assigned the proper shipping name Cyanogen in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.3 Toxic Gas material. Required label(s): 2.3, 2.1.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 119)

Hazards: TOXIC. May be fatal if inhaled or absorbed through skin. Flammable. Vapors heavier than air.

Fire: Small: dry chemical or CO2. Large: water spray or fog. Fight from maximum distance.

Spill: Do not touch. Stop leak if safe. Use water spray to reduce vapor.

Chemical and Physical Properties

Cyanogen appears as a colorless gas with an odor of almonds. Freezes at -28 °C and boils at -20.7 °C. Shipped as a liquid confined under its vapor pressure. The gas is heavier than air and a flame can travel back to the source of leak very easily. Prolonged exposure to fire or intense heat may cause the containers to violently rupture and rocket. Used to make other chemicals, as a fumigant, and as a rocket propellant.

CAS Number: 460-19-5
Molecular Formula: C2N2
Molecular Weight: 52.03 g/mol
Color / Form: Colorless gas; burns with purple tinged flame
Odor: Almond-like odor, which is acrid and pungent in lethal concentrations
Boiling Point: -6.1 F
Melting Point: -18.2 °F (USCG, 1999)
Flash Point: Flammable gas
Specific Gravity: 0.954 at -5.8 F
Vapor Pressure: 5.1 atm at 70 F
Vapor Density: 1.82 (heavier than air)
Water Solubility: 1 %
Log P: log Kow = 0.07

Regulatory Data

CERCLA RQ (40 CFR 302.4)
100 lb
OSHA PEL
none
NIOSH REL
TWA 10 ppm (20 mg/m 3 )
IDLH
N
RCRA Waste Code(s)
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A release of this material at or above its CERCLA reportable quantity (100 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: 2. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 1026 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.